Dental implant treatment, performed upon loss of a natural tooth and by implanting an artificial tooth root (implant body) in the jawbone at the location of tooth loss and using the artificial tooth root as a base to mount an artificial tooth thereon, has been conventionally known.
With the dental implant treatment that is currently being practiced, after surgically excising the gum above the jawbone (alveolar bone), an implant body of a size determined beforehand by examination is implanted in the jawbone and thereafter, there is a necessary waiting period of three months to six months for integration (osseointegration) of the implant body and the jawbone. Treatment is then performed through the procedures of mounting a pedestal, referred to as an. “abutment body,” on the implant body that has integrated with the jawbone and mounting an artificial tooth that has been molded to a predetermined size in advance on the abutment body.
The dental implant treatment is performed in accordance with these procedures and therefore six months to one year are generally required as a treatment, period.
Also, depending on the patient, the bone amount (especially the bone thickness) required for implanting the implant body may be insufficient, especially in the case of performing treatment on the maxilla. In this case, first, an auxiliary operation, such as a guided bone regeneration method (GBR method), ridge expansion, socket lifting, sinus lifting, etc., is performed on the jawbone and the dental implant treatment is performed upon forming the necessary bone amount, thus requiring an additional treatment period of several months.
As a dental implant treatment that does not require such an auxiliary operation, the art described in Patent Document 1 is proposed.
The art described in Patent Document 1 is: “A dental component implant having a composite structure that includes three leg implant bodies, implanted and fixed as tooth roots in the alveolar bone of a maxilla molar portion and forming a leg structure, a tooth root pedestal portion, provided with keeping holes of inner diameters greater than the outer diameters of the leg implant bodies to enable the leg implant bodies to be inserted movably and having a function of integrating the respective leg implant bodies inserted in the keeping holes, and an abutment, which is a supporting base coupled to the tooth root pedestal portion and on which a tooth crown is loaded.”
In summary, the art is a dental component, implant having a composite structure with which there are three implant bodies that are implanted as tooth roots in the alveolar bone, the three implant bodies are integrated by the tooth root pedestal portion, and an abutment is added to these components.
The following effects are obtained by this art: “Implantation is possible regardless of the shape of the maxilla or the mandible or the position of the inferior alveolar nerve running at a lower portion of the mandible, and by the plurality of leg implant bodies supporting the tooth root pedestal portion, the occlusion load is dispersed among the respective leg implant bodies to prevent biased concentration of stress and the load is applied to a major axis direction of the abutment so that the life of the implant as a whole is elongated. Additional operation by the guided bone regeneration method for an increase of bone amount, etc., is thereby made unnecessary and application of implant implantation for cases of insufficient bone amount or cases unsuitable for implantation is made possible.”
However, with the art described in Patent Document 1, although auxiliary operation by the guided bone regeneration method, etc., for cases of insufficient bone amount or cases unsuitable for implantation is made unnecessary, the period for integration of the implant bodies and the jawbone is still required and the problem that six months to one year are required as the treatment period still remains.
On the other hand, the arts described in Patent Document 2 are proposed in regard to a dental implant treatment that does not require a period for integration of the implant bodies and the jawbone.
An art described in Patent Document 2 is: “An artificial tooth fixture including a locking shaft, driven into an upper alveolar bone, which, among the alveolar bones, faces the oral cavity side, and an abutment having the locking shaft projecting integrally from a lower end and having an artificial tooth mounted, on an upper portion thereof.” Further, “a locking shaft made up of a plurality of shafts, with each locking shaft having locking barb projections at a tip and a plurality of locations in a longitudinal direction of an outer periphery of the shaft,” is also proposed.
The following effects are obtained by these arts: “An abutment can be mounted on an upper alveolar bone immediately without waiting for a period of several months for the integration of the implant material and the alveolar bone as in the conventional case.” Further, “the locking shaft has locking barb projections at the tip and the plurality of locations in the longitudinal direction of the outer periphery of the shaft, and therefore the driving of the locking shaft into the alveolar bone can be facilitated and the force of binding of the abutment to the alveolar bone by the locking shaft can be made sufficiently high.”
However, with the art described in patent Document 2, the locking shaft provided on the abutment cannot be fixed unless it is driven considerably deeply into the alveolar bone, and even, if barb projections are provided on the locking shaft, although the possibility of coming off is decreased, the locking shaft must be driven strongly into the alveolar bone using a hammer, etc., and there is thus the problem that not only is fixing insufficient but a large burden is also placed on the bone.
An art with the theme of lightening the burden on the bone has also been proposed.
The art described, in Patent Document, 3 is: “A dental implant with which a body portion of the implant is planted in a bone and a head portion of the implant is projected above the bone, the implant being arranged so that single surfaces of the respective head portions of two implants are clasped together and the body portions of the implants form a truncated chevron shape, the form of the character of 8 of a Japanese numeral, inside the bone in this state.”
The following effects are obtained by this art: “An implant can be provided, with which initial fixing is secured without requiring expertise by removing just the necessary amount of bone at the location of planting of the implant and implanting the implant body easily without causing the implant to sink in more than necessary and with which the force applied to the implant in the vertical direction due to subsequent occlusal pressure is relaxed to prevent perturbation and sinking of the implant and increase the establishment of long-term functioning within the oral cavity.”
However, with the art described in Patent Document 3, a specialized circular cutting tool must be used to dig a groove for planting the body portion of the implant. There is also the problem that the process of digging a groove in a jawbone is a process that a dentist, does not have experience in and is thus extremely difficult. Further, even with the art. a period for integration of the implant body and the jawbone is required and therefore a long period is still required as the treatment period.